It started about 3 months ago. My 850 turbo started hesitating, bucking and stumbling while accelerating. There was certain condition before it would start happening. At random times, it would start bucking and hesitating. I could mash the accelerator and everything would smooth out. About a month after it started, the fuel pump went bad! I replaced it and the filter and thing were good for a while. Then the symptoms came back. A week later it left me stranded. Would not start. I checked and it had fuel and fuel pressure. I eventually tried a camshaft sensor, plugs and wires. Cranked it and it started up without a problem! It has been running great for a month and today the symptoms returned!!! I'm running out of ideas.... Someone please give me some idea of what is going on.